Add Flamegraph HTML to Uploaded Profile Data

[artursarlo]

Add Flamegraph HTML to Uploaded Profile Data

Summary

Includes the flamegraph HTML as a field (flamegraph_html) inside the profile metadata that is uploaded with each snapshot. This allows consumers of the uploaded data to render the flamegraph directly from the profile payload without regenerating it client-side.

Additionally, the flamegraph template has been updated to be fully responsive.

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Changes

gprofiler/merge.py

• Added flamegraph_html: Optional[str] as a parameter to _make_profile_metadata, concatenate_profiles, and merge_profiles.
• The value is threaded through to the serialized profile metadata JSON comment (# {...}) under the key "flamegraph_html".
• Defaults to None in the public-facing functions to preserve backward compatibility.

gprofiler/main.py

• Extracted _generate_flamegraph_html() method: Splits flamegraph generation logic out of _generate_output_files() into a standalone method that accepts stripped collapsed stack data and start/end times, returning the rendered HTML string or None on failure (with a warning log).
• Refactored _generate_output_files(): Now delegates to _generate_flamegraph_html() instead of inlining the generation logic.
• Pre-generation in _snapshot(): Before producing the final merged result, a temporary merge is performed using the same NoopProfiler/perf branching logic to obtain the full collapsed stacks. The flamegraph HTML is generated from this temporary result and passed to the final concatenate_profiles / merge_profiles calls via the new flamegraph_html parameter.

gprofiler/resources/flamegraph/flamegraph_template.html

• Made the flamegraph chart responsive: chart width is now computed dynamically as max(1400, window.innerWidth * 0.98) instead of a fixed 960px.
• Added a resize event listener to reflow the chart on window resize.
• Updated container layout: max-width/width set to 99%, reduced horizontal padding, added margin: 0 to body.

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Motivation

The intel_dynamic_profiling ad-hoc flow uploads snapshots to a backend. Previously, the flamegraph was only written to disk when --flamegraph was enabled; the uploaded metadata had no HTML representation of the call stacks. This change embeds the pre-rendered HTML in the upload payload so the backend can surface the flamegraph without any additional processing.

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Testing

• When --flamegraph is enabled, the uploaded profile's metadata JSON will contain a flamegraph_html key with the full HTML string.
• When --flamegraph is disabled or flamegraph generation fails, flamegraph_html is null in the metadata.
• Existing output file behavior (.col and .html files written to --output-dir) is unchanged.